/*
 * Copyright (c) 2001-2003 Michael David Adams.
 * All rights reserved.
 */

/* __START_OF_JASPER_LICENSE__
 * 
 * JasPer License Version 2.0
 * 
 * Copyright (c) 2001-2006 Michael David Adams
 * Copyright (c) 1999-2000 Image Power, Inc.
 * Copyright (c) 1999-2000 The University of British Columbia
 * 
 * All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person (the
 * "User") obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, and/or sell copies of the Software, and to permit
 * persons to whom the Software is furnished to do so, subject to the
 * following conditions:
 * 
 * 1.  The above copyright notices and this permission notice (which
 * includes the disclaimer below) shall be included in all copies or
 * substantial portions of the Software.
 * 
 * 2.  The name of a copyright holder shall not be used to endorse or
 * promote products derived from the Software without specific prior
 * written permission.
 * 
 * THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS
 * LICENSE.  NO USE OF THE SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER
 * THIS DISCLAIMER.  THE SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS
 * "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.  IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL
 * INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING
 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.  NO ASSURANCES ARE
 * PROVIDED BY THE COPYRIGHT HOLDERS THAT THE SOFTWARE DOES NOT INFRINGE
 * THE PATENT OR OTHER INTELLECTUAL PROPERTY RIGHTS OF ANY OTHER ENTITY.
 * EACH COPYRIGHT HOLDER DISCLAIMS ANY LIABILITY TO THE USER FOR CLAIMS
 * BROUGHT BY ANY OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL
 * PROPERTY RIGHTS OR OTHERWISE.  AS A CONDITION TO EXERCISING THE RIGHTS
 * GRANTED HEREUNDER, EACH USER HEREBY ASSUMES SOLE RESPONSIBILITY TO SECURE
 * ANY OTHER INTELLECTUAL PROPERTY RIGHTS NEEDED, IF ANY.  THE SOFTWARE
 * IS NOT FAULT-TOLERANT AND IS NOT INTENDED FOR USE IN MISSION-CRITICAL
 * SYSTEMS, SUCH AS THOSE USED IN THE OPERATION OF NUCLEAR FACILITIES,
 * AIRCRAFT NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL
 * SYSTEMS, DIRECT LIFE SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH
 * THE FAILURE OF THE SOFTWARE OR SYSTEM COULD LEAD DIRECTLY TO DEATH,
 * PERSONAL INJURY, OR SEVERE PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH
 * RISK ACTIVITIES").  THE COPYRIGHT HOLDERS SPECIFICALLY DISCLAIM ANY
 * EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR HIGH RISK ACTIVITIES.
 * 
 * __END_OF_JASPER_LICENSE__
 */

/******************************************************************************\
* Includes.
\******************************************************************************/

#include <assert.h>
#include <ctype.h>

#include "jasper/jas_tvp.h"
#include "jasper/jas_stream.h"
#include "jasper/jas_image.h"
#include "jasper/jas_string.h"

#include "pgx_cod.h"

/******************************************************************************\
* Local prototypes.
\******************************************************************************/

static int pgx_gethdr(jas_stream_t *in, pgx_hdr_t *hdr);
static int pgx_getdata(jas_stream_t *in, pgx_hdr_t *hdr, jas_image_t *image);
static int_fast32_t pgx_getword(jas_stream_t *in, bool bigendian, int prec);
static int pgx_getsgnd(jas_stream_t *in, bool *sgnd);
static int pgx_getbyteorder(jas_stream_t *in, bool *bigendian);
static int pgx_getc(jas_stream_t *in);
static int pgx_getuint32(jas_stream_t *in, uint_fast32_t *val);
static jas_seqent_t pgx_wordtoint(uint_fast32_t word, int prec, bool sgnd);

/******************************************************************************\
* Code for load operation.
\******************************************************************************/

/* Load an image from a stream in the PGX format. */

jas_image_t *pgx_decode(jas_stream_t *in, char *optstr)
{
    jas_image_t *image;
    pgx_hdr_t hdr;
    jas_image_cmptparm_t cmptparm;

    /* Avoid compiler warnings about unused parameters. */
    optstr = 0;

    image = 0;

    if (pgx_gethdr(in, &hdr)) {
        goto error;
    }

#ifdef PGX_DEBUG
    pgx_dumphdr(stderr, &hdr);
#endif

    if (!(image = jas_image_create0())) {
        goto error;
    }
    cmptparm.tlx = 0;
    cmptparm.tly = 0;
    cmptparm.hstep = 1;
    cmptparm.vstep = 1;
    cmptparm.width = hdr.width;
    cmptparm.height = hdr.height;
    cmptparm.prec = hdr.prec;
    cmptparm.sgnd = hdr.sgnd;
    if (jas_image_addcmpt(image, 0, &cmptparm)) {
        goto error;
    }
    if (pgx_getdata(in, &hdr, image)) {
        goto error;
    }

    jas_image_setclrspc(image, JAS_CLRSPC_SGRAY);
    jas_image_setcmpttype(image, 0,
      JAS_IMAGE_CT_COLOR(JAS_CLRSPC_CHANIND_GRAY_Y));

    return image;

error:
    if (image) {
        jas_image_destroy(image);
    }
    return 0;
}

/******************************************************************************\
* Code for validate operation.
\******************************************************************************/

int pgx_validate(jas_stream_t *in)
{
    uchar buf[PGX_MAGICLEN];
    uint_fast32_t magic;
    int i;
    int n;

    assert(JAS_STREAM_MAXPUTBACK >= PGX_MAGICLEN);

    /* Read the validation data (i.e., the data used for detecting
      the format). */
    if ((n = jas_stream_read(in, buf, PGX_MAGICLEN)) < 0) {
        return -1;
    }

    /* Put the validation data back onto the stream, so that the
      stream position will not be changed. */
    for (i = n - 1; i >= 0; --i) {
        if (jas_stream_ungetc(in, buf[i]) == EOF) {
            return -1;
        }
    }

    /* Did we read enough data? */
    if (n < PGX_MAGICLEN) {
        return -1;
    }

    /* Compute the signature value. */
    magic = (buf[0] << 8) | buf[1];

    /* Ensure that the signature is correct for this format. */
    if (magic != PGX_MAGIC) {
        return -1;
    }

    return 0;
}

/******************************************************************************\
*
\******************************************************************************/

static int pgx_gethdr(jas_stream_t *in, pgx_hdr_t *hdr)
{
    int c;
    uchar buf[2];

    if ((c = jas_stream_getc(in)) == EOF) {
        goto error;
    }
    buf[0] = c;
    if ((c = jas_stream_getc(in)) == EOF) {
        goto error;
    }
    buf[1] = c;
    hdr->magic = buf[0] << 8 | buf[1];
    if (hdr->magic != PGX_MAGIC) {
        goto error;
    }
    if ((c = pgx_getc(in)) == EOF || !isspace(c)) {
        goto error;
    }
    if (pgx_getbyteorder(in, &hdr->bigendian)) {
        goto error;
    }
    if (pgx_getsgnd(in, &hdr->sgnd)) {
        goto error;
    }
    if (pgx_getuint32(in, &hdr->prec)) {
        goto error;
    }
    if (pgx_getuint32(in, &hdr->width)) {
        goto error;
    }
    if (pgx_getuint32(in, &hdr->height)) {
        goto error;
    }
    return 0;

error:
    return -1;
}

static int pgx_getdata(jas_stream_t *in, pgx_hdr_t *hdr, jas_image_t *image)
{
    jas_matrix_t *data;
    uint_fast32_t x;
    uint_fast32_t y;
    uint_fast32_t word;
    int_fast32_t v;

    data = 0;

    if (!(data = jas_matrix_create(1, hdr->width))) {
        goto error;
    }
    for (y = 0; y < hdr->height; ++y) {
        for (x = 0; x < hdr->width; ++x) {
            /* Need to adjust signed value. */
            if ((v = pgx_getword(in, hdr->bigendian, hdr->prec)) < 0) {
                goto error;
            }
            word = v;
            v = pgx_wordtoint(word, hdr->prec, hdr->sgnd);
            jas_matrix_set(data, 0, x, v);
        }
        if (jas_image_writecmpt(image, 0, 0, y, hdr->width, 1, data)) {
            goto error;
        }
    }
    jas_matrix_destroy(data);
    return 0;

error:
    if (data) {
        jas_matrix_destroy(data);
    }
    return -1;
}

static int_fast32_t pgx_getword(jas_stream_t *in, bool bigendian, int prec)
{
    uint_fast32_t val;
    int i;
    int j;
    int c;
    int wordsize;

    wordsize = (prec + 7) / 8;

    if (prec > 32) {
        goto error;
    }

    val = 0;
    for (i = 0; i < wordsize; ++i) {
        if ((c = jas_stream_getc(in)) == EOF) {
            goto error;
        }
        j = bigendian ? (wordsize - 1 - i) : i;
        val = val | ((c & 0xff) << (8 * j));
    }
    val &= (1 << prec) - 1;
    return val;

error:
    return -1;
}

static int pgx_getc(jas_stream_t *in)
{
    int c;
    for (;;) {
        if ((c = jas_stream_getc(in)) == EOF) {
            return -1;
        }
        if (c != '#') {
            return c;
        }
        do {
            if ((c = jas_stream_getc(in)) == EOF) {
                return -1;
            }
        } while (c != '\n' && c != '\r');
    }
}

static int pgx_getbyteorder(jas_stream_t *in, bool *bigendian)
{
    int c;
    char buf[2];

    do {
        if ((c = pgx_getc(in)) == EOF) {
            return -1;
        }
    } while (isspace(c));

    buf[0] = c;
    if ((c = pgx_getc(in)) == EOF) {
        goto error;
    }
    buf[1] = c;
    if (buf[0] == 'M' && buf[1] == 'L') {
        *bigendian = true;
    } else if (buf[0] == 'L' && buf[1] == 'M') {
        *bigendian = false;
    } else {
        goto error;
    }

    while ((c = pgx_getc(in)) != EOF && !isspace(c)) {
        ;
    }
    if (c == EOF) {
        goto error;
    }
    return 0;

error:
    return -1;
}

static int pgx_getsgnd(jas_stream_t *in, bool *sgnd)
{
    int c;

    do {
        if ((c = pgx_getc(in)) == EOF) {
            return -1;
        }
    } while (isspace(c));

    if (c == '+') {
        *sgnd = false;
    } else if (c == '-') {
        *sgnd = true;
    } else {
        goto error;
    }
    while ((c = pgx_getc(in)) != EOF && !isspace(c)) {
        ;
    }
    if (c == EOF) {
        goto error;
    }
    return 0;

error:
    return -1;
}

static int pgx_getuint32(jas_stream_t *in, uint_fast32_t *val)
{
    int c;
    uint_fast32_t v;

    do {
        if ((c = pgx_getc(in)) == EOF) {
            return -1;
        }
    } while (isspace(c));

    v = 0;
    while (isdigit(c)) {
        v = 10 * v + c - '0';
        if ((c = pgx_getc(in)) < 0) {
            return -1;
        }
    }
    if (!isspace(c)) {
        return -1;
    }
    *val = v;

    return 0;
}

static jas_seqent_t pgx_wordtoint(uint_fast32_t v, int prec, bool sgnd)
{
    jas_seqent_t ret;
    v &= (1 << prec) - 1;
    ret = (sgnd && (v & (1 << (prec - 1)))) ? (v - (1 << prec)) : v;
    return ret;
}
